This article talks about how companies decide on their size and how they work inside and outside their boundaries. Traditional theories focus on cost, but newer ideas, like the Knowledge-Based Theory of the Firm (KBT), from the mid-1990s, look at a more complete view that fits the modern knowledge-based economy. The KBT helps us understand how firms create value and where their limits are. It may not fully explain why firms exist, but it's great for seeing how firms make boundaries and add value.